Subcutaneous cavity marking device and method

ABSTRACT

These are subcutaneous cavity marking devices and methods. More particularly, upon insertion into a body, the cavity marking device and method enable one to determine the center, orientation, and periphery of the cavity by radiographic, mammographic, echogenic, or other non-invasive imaging techniques. Also, the device contains a bioabsorbable or non-bioabsorbable marker. The device may be combined with various substances enhancing the radiopaque, mammographic, or echogenic characteristics of the marker or the body allowing it to be observed by any non-invasive imaging techniques. This is further a method of marking a subcutaneous cavity using a bioabsorbable material and a bioabsorbable or non-bioabsorbable marker in conjunction with the material. The method also may combine any of the features as described with the device.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Ser. No. 09/220,618,filed Dec. 24, 1998 now abandoned.

FIELD OF THE INVENTION

This invention is directed to subcutaneous cavity marking devices andmethods. More particularly, a cavity marking device and method isdisclosed that enable one to determine the location, orientation, andperiphery of the cavity by radiographic, mammographic, echographic, orother non-invasive techniques. The invention typically is made up of oneor more resilient bodies and a radiopaque or echogenic marker.

BACKGROUND OF THE INVENTION

Over 1.1 million breast biopsies are performed each year in the UnitedStates alone. Of these, about 80% of the lesions excised during biopsyare found to be benign while about 20% of these lesions are malignant.

In the field of breast cancer, stereotactically guided and percutaneousbiopsy procedures have increased in frequency as well as in accuracy asmodern imaging techniques allow the physician to locate lesions withever-increasing precision. However, for any given biopsy procedure, asubsequent examination of the biopsy site is very often desirable. Thereis an important need to determine the location, most notably the center,as well as the orientation and periphery (margins) of the subcutaneouscavity from which the lesion is removed.

In those cases where the lesion is found to be benign, for example, afollow-up examination of the biopsy site is often performed to ensurethe absence of any suspect tissue and the proper healing of the cavityfrom which the tissue was removed. This is also the case where thelesion is found to be malignant and the physician is confident that allsuspect tissue was removed and the tissue in the region of the perimeteror margins of the cavity is “clean”.

In some cases, however, the physician may be concerned that the initialbiopsy failed to remove a sufficient amount of the lesion. Such a lesionis colloquially referred to as a “dirty lesion” or “dirty margin” andrequires follow-up observation of any suspect tissue growth in thesurrounding marginal area of the initial biopsy site. Thus, are-excision of the original biopsy site must often be performed. In sucha case, the perimeter of the cavity must be identified since the cavitymay contain cancerous cells. Identification of the cavity perimeternecessary to avoid the risk of opening the cavity, which could releaseand spread cancerous cells. Moreover, the site of the re-excisedprocedure itself requires follow-up examination, providing furtherimpetus for accurate identification of the location of the re-excisedsite. Therefore, a new marker will be placed after re-excision.

Prior methods of marking biopsy cavities utilize one or more tissuemarking clips as the biopsy site marking device. Most commonly, thesemarker clips have a “horseshoe” configuration. The marker clips attachto the walls of the cavity when the free ends or limbs of the“horseshoe” are pinched together, trapping the tissue. This device hassignificant drawbacks.

For instance, prior to placing the marker clip at the cavity site, thesite must be thoroughly cleaned, typically by vacuum, to remove anyresidual tissue debris. This minimizes the possibility that the markerclip attaches to any loose tissue as opposed to the cavity wall. Oncethe cavity is prepared, the clip must be examined to ensure that thelimbs of the clip are substantially straight. If the limbs have beenprematurely bent together, the clip will be discarded since it will mostlikely not attach properly to the cavity wall. Actual placement of theclip often requires additional vacuum of the cavity wall to draw thewall into the aperture between the limbs of the marking clip so that abetter grip is obtained between the limbs of the clip. Additionally,there is always the possibility that the clip may detach from the cavitywall during or after withdrawal of the tools used to place the clip intothe cavity.

Aside from the problems inherent in the placement of the marking clip,there are also limitations associated with how well the marking clip canidentify a biopsy cavity. As the marking clip must trap tissue forproper attachment, in cases of endoscopic placement, the clip can onlybe placed on a wall of the cavity substantially opposite to the openingof the cavity.

Moreover, patient concern limits the number of clips that may be placedin a cavity. As a result, the medical practitioner is forced to identifythe outline of a three dimensional cavity by a single point as definedby the marking clip. Obviously, determination of the periphery of abiopsy cavity from one point of the periphery is not possible.

These limitations are compounded as the biopsy cavity fills within a fewhours with bodily fluids, which eventually renders the cavity invisibleto non-invasive techniques. Another difficulty in viewing the clip stemsfrom the fact that the clip is attached to the side, not the center, ofthe cavity. This makes determining the spatial orientation and positionof the cavity difficult if not impossible during follow-up examination.Additionally, during a stereotactic breast biopsy procedure, the breastis under compression when the marking clip is placed. Upon release ofthe compressive force, determining the location of the clip can beunpredictable, and the orientation as well as the location of theperiphery of the cavity are lost.

The marker clip does not aid in the healing process of the biopsy wound.Complications may arise if the marker strays from its original placementsite. As described above, if a re-excision of the site is required, themarker clip may also interfere when excision of a target lesion issought.

Other devices pertaining to biopsy aids are directed to assisting in thehealing and closure of the biopsy wound; thus they do not aid theclinical need or desirability of accurately preserving the location andorientation of the biopsy cavity. See, e.g., U.S. Pat. Nos. 4,347,234,5,388,588, 5,326,350, 5,394,886, 5,467,780, 5,571,181, and 5,676,146.

SUMMARY OF THE INVENTION

This invention relates to devices and procedures for percutaneouslymarking a biopsy cavity. In particular, the inventive device is a biopsycavity-marking body made of a resilient, preferably bioabsorbablematerial having at least one preferably radiopaque or echogenic marker.The device may take on a variety of shapes and sizes tailored for thespecific biopsy cavity to be filled. For example, the device in itssimplest form is a spherical or cylindrical collagen sponge having asingle radiopaque or echogenic marker located in its geometric center.Alternatively, the body may have multiple components linked togetherwith multiple radiopaque or echogenic markers.

A further aspect of the invention allows the marker or the body, singlyor in combination, to be constructed to have a varying rate ofdegradation or bioabsorption. For instance, the body may be constructedto have a layer of bioabsorbable material as an outer “shell.”Accordingly, prior to degradation of the shell, the body is palpable.Upon degradation of the shell, the remainder of the body would degradeat an accelerated rate in comparison to the outer shell.

The device may additionally contain a variety of drugs, such ashemostatic agents, pain-killing substances, or even healing ortherapeutic agents that may be delivered directly to the biopsy cavity.Importantly, the device is capable of accurately marking a specificlocation, such as the center, of the biopsy cavity, and providing otherinformation about the patient or the particular biopsy or devicedeployed.

The device is preferably, although not necessarily, deliveredimmediately after removal of the tissue specimen using the same deviceused to remove the tissue specimen itself Such devices are described inpending U.S. patent application Ser. No. 09/145,487 (Attorney Docket No.41269-20002.00), filed Sep. 1, 1998 and entitled “PERCUTANEOUS TISSUEREMOVAL DEVICE”, and pending U.S. patent application Ser. No. 09/184,766(Attorney Docket No. 41269-20001.20), filed Nov. 2, 1998 and entitled“EXPANDABLE RING PERCUTANEOUS TISSUE REMOVAL DEVICE” the entirety ofeach are which hereby incorporated by reference. The device iscompressed and loaded into the access device and percutaneously advancedto the biopsy site where, upon exiting from the access device, itexpands to substantially fill the cavity of the biopsy. Follow-upnoninvasive detection techniques, such as x-ray mammography orultrasound may then be used by the physician to identify, locate, andmonitor the biopsy cavity site over a preferred period of time.

The device is usually inserted into the body either surgically via anopening in the body cavity, or through a minimally invasive procedureusing such devices as a catheter, introducer or similar type device.When inserted via the minimally invasive procedure, the resiliency ofthe body allows the device to be compressed upon placement in a deliverydevice. Upon insertion of the cavity marking device into the cavity, theresiliency of the body causes the cavity marking device to self-expand,substantially filling the cavity. The resiliency of the body can befurther pre-determined so that the body is palpable, thus allowingtactile location by a surgeon in subsequent follow-up examinations.Typically, the filler body is required to be palpable for approximately3 months. However, this period may be increased or decreased as needed.

The expansion of the resilient body can be aided by the addition of abio-compatible fluid which is absorbed into the body. For instance, thefluid can be a saline solution, a painkilling substance, a healingagent, a therapeutic fluid, or any combination of such fluids. The fluidor combination of fluids may be added to and absorbed by the body of thedevice before or after deployment of the device into a cavity. Forexample, the body of the device may be pre-soaked with the fluid andthen delivered into the cavity. In this instance, the fluid aids theexpansion of the body of the device upon deployment. Another example isprovided as the device is delivered into the cavity without beingpre-soaked. In such a case, fluid is delivered into the cavity after thebody of the device is deployed into the cavity. Upon delivery of thefluid, the body of the device soaks the fluid, thereby aiding theexpansion of the cavity marking device as it expands to fit the cavity.The fluid may be, but is not limited to being, delivered by the accessdevice.

By “bio-compatible fluid” what is meant is a liquid, solution, orsuspension that may contain inorganic or organic material. For instance,the bio-compatible fluid is preferably saline solution, but may be wateror contain adjuvants such as medications to prevent infection, reducepain, or the like. Obviously, the liquid is intended to be a type thatdoes no harm to the body.

After placement of the cavity marking device into the cavity, thebioabsorbable body degrades at a predetermined rate. As the body of thecavity marking device is absorbed, tissue is substituted for thebioabsorbable material. Moreover, while the body degrades, the marker,which is usually suspended substantially in the volumetric center of thebody of the device, is left in the center of the cavity. Thus, during asubsequent examination, a medical practitioner having knowledge of thedimensions of the body of the cavity marking device can determine thelocation as well as the periphery of the biopsy cavity. The orientationof the cavity is self-evident as the marker is left in substantially thecenter of the cavity. For the case where multiple markers are used, themarkers are usually placed in a manner showing directionality.

Both the body and the marker can be made, via radiopaque or echogeniccoatings or in situ, to degrade and absorb into the patient's body overa predetermined period of time. It is generally preferred that if themarker's radiopacity or echogenicity is chosen to degrade over time,such degradation does not take place within at least one year afterimplantation of the inventive device. In this way, if a new lump orcalcification (in the case of a breast biopsy) is discovered after thebiopsy, such a marker will allow the physician to know the relation ofsuch new growth in relation to the region of excised tissue. On theother hand, and as discussed below, a bioabsorption period of threemonths is preferred for any such coatings on the perimeter of the bodyitself.

This invention further includes the act of filling the biopsy cavitywith a bioabsorbable liquid, aerosol or gelatinous material, preferablygelatinous collagen, allowing the material to partially solidify or geland then placing a marker, which may have a configuration as describedabove, into the center of the bioabsorbable material. The gel may alsobe made radiopaque or echogenic by the addition of radiopaque materials,such as barium- or bismuth-containing compounds and the like, as well asparticulate radio-opaque fillers, e.g., powdered tantalum or tungsten,barium carbonate, bismuth oxide, barium sulfate, to the gel.

This method may be combined with any aspect of the previously describeddevices as needed. For instance, one could insert a hemostatic orpain-killing substance as described above into the biopsy cavity alongwith the bioabsorbable material. Alternatively, a bioabsorbable markercould be inserted into a predetermined location, such as the center, ofthe body of bioabsorbable material.

It is within the scope of this invention that either or both of themarker or markers and the bioabsorbable body may be radioactive, if aregimen of treatment using radioactivity is contemplated.

This procedure may be used in any internal, preferably soft, tissue, butis most useful in breast tissue, lung tissue, prostate tissue, lymphgland tissue, etc. Obviously, though, treatment and diagnosis of breasttissue problems forms the central theme of the invention.

In contrast to the marker clips as described above, the cavity markingdevice has the obvious advantage of marking the geometric center of abiopsy cavity. Also, unlike the marking clip which has the potential ofattaching to loose tissue and moving after initial placement, themarking device self-expands upon insertion into the cavity, thusproviding resistance against the walls of the cavity thereby anchoringitself within the cavity. The marking device may be configured to besubstantially smaller, larger, or equal to the size of the cavity,however, in some cases the device will be configured to be larger thanthe cavity. This aspect of the biopsy marking device provides a cosmeticbenefit to the patient, especially when the biopsy is taken from thebreast. For example, the resistance provided by the cavity markingdevice against the walls of the cavity may minimize any “dimpling”effect observed in the skin when large pieces of tissue are removed, as,for example, during excisional biopsies.

Although the subcutaneous cavity marking device and method describedabove are suited for percutaneous placement of the marker within abiopsy cavity it is not intended that the invention is limited to suchplacement. The device and method are also appropriate forintra-operative or surgical placement of the marker within a biopsycavity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a tissue cavity marking device with a spherical bodyand a single centrally-located marker.

FIG. 1B shows a tissue cavity marking device with a cylindrical body andtwo ring-shaped markers aligned near the cylinder's longitudinal axis.

FIG. 1C shows another tissue cavity marking device with a multi-faced orirregular body and a single centrally-located marker.

FIG. 1D illustrates a tissue cavity marking device with a body havingpores.

FIG. 1E is a partial cross-sectional view of FIG. 1D.

FIG. 1F illustrates a tissue cavity marking device with a body having anouter shell of a bioabsorbable material.

FIGS. 2A-2F illustrate various configurations of the marker.

FIG. 3A illustrates a cavity marking device having multiple bodycomponents traversed by a single wire or suture marker, or multiplewires or suture markers.

FIG. 3B illustrates a cavity marking device having a helically woundwire or suture marker.

FIG. 3C illustrates a cavity marking device having wire or suturemarkers on the perimeter of the body.

FIG. 3D illustrates a cavity marking device having wire or markers onthe ends of the body.

FIGS. 4A-4C illustrate a method of marking a biopsy tissue cavity withthe device of the present invention.

FIGS. 4D-4F illustrate a method of marking a biopsy tissue cavity withthe device of the present invention wherein a bio-compatible fluid isdelivered to the cavity marking device after placement.

FIGS. 4G-4I illustrate a method of marking a biopsy tissue cavity withthe device of the present invention wherein a bio-compatible fluid isused to push the cavity marking device out of the access device and intothe biopsy tissue cavity.

FIGS. 4J-4L illustrate a method of marking a biopsy tissue cavity withthe device of the present invention wherein the body material of themarking device is deposited into the biopsy cavity prior to theplacement of the marker within the biopsy device.

FIGS. 5A-B illustrate a spherical wire marking device for deploymentwithout a filler body into a tissue cavity.

FIG. 5C illustrates a cylindrical wire marking device for deploymentwithout a filler body into a tissue cavity.

FIGS. 5D-E illustrate a helical coil wire marking device for deploymentwithout a filler body into a tissue cavity.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A-1C show various configurations of a preferred subcutaneouscavity marking device of the present invention. Here the marking device(100) is displayed as having either a generally spherical body (102)(FIG. 1A), a generally cylindrical body (104) (FIG. 1B), or amulti-faced or irregular body (106) (FIG. 1C). In general, it is withinthe scope of this invention for the body to assume a variety of shapes.For example, the body may be constructed to have substantially curvedsurfaces, such as the preferred spherical (102) and cylindrical (104)bodies of FIGS. 1A and 1B, respectively. The body may have conical orellipsoidal, etc. shapes as well. It is further within the scope of thisinvention for the body to have substantially planar surfaces, such aspolyhedric (i.e. cubic, tetrahedral, etc.) or prismatic, etc. forms.Finally, the body may also have an irregular or random shape, in thecase of a gel, combining features of various curved and planar surfaces.Body (106) of FIG. 1C is an example of such an irregular body shape. Theparticular body shape will be chosen to best match to the biopsy cavityin which the device is placed. However, it is also contemplated that thebody shape can be chosen to be considerably larger than the cavity.Therefore, expansion of the device will provide a significant resistanceagainst the walls of the cavity. Moreover, the aspect ratio of thedevice is not limited to what is displayed in the figures. For example,the cylindrical body (104) may have a shorter or longer length asrequired.

In the bodies of FIGS, 1A and 1C, the generally spherical marker (150)is located at or near the geometric center of the body. Such aconfiguration will aid the physician in determining the exact locationof the biopsy cavity, even after the body degrades and is absorbed intothe human or mammalian body.

In the case of the ring-shaped markers (154) of FIG. 1B, they aregenerally aligned along the longitudinal axis (114) of body (104). Notethat although the ring-shaped markers (154) are spatially oriented sothat the longitudinal axis (114) of the body (104) lies along thelongitudinal axes (not shown) of each marker (154), each marker mayindividually or together assume a wide variety of random orpredetermined spatial orientations other than the aligned orientation asseen in FIG. 1C. It can be appreciated that any asymmetric marker suchas marker (154) is useful in aiding a physician to determine the spatialorientation of the deployed inventive device.

Obviously, marker (150), (154) may reside in locations other than thosedemonstrated in FIGS, 1A-1C. It is, however, preferred that markers(150), (154) dwell in a predetermined, preferably central, location andorientation in the device body so to aid the physician in determiningthe location and orientation of the biopsy cavity. The markers hereindescribed may be affixed to the interior or on the surface of the bodyby any number of suitable methods. For instance, the marker may bemerely suspended in the interior of the body (especially in the casewhere the body is a gel), it may be woven into the body (especially inthe case where the marker is a wire or suture), it may be press fit ontothe body (especially in the case where the marker is a ring or band), orit may affixed to the body by a biocompatible adhesive. Any suitablemeans to affix or suspend the marker into the body in the preferredlocation is within the scope of the present invention.

Tissue regrowth in a particular orientation can also be promoted by abody design shown in FIG. 1D. Here, body (110) contains a number ofpores (138) through which tissue may grow. The pores may also be alignedin a substantially parallel fashion, traversing the thickness of thebody so that tissue may regrow from one side of the body through to theother side. This is demonstrated in inset FIG. 1E, which shows a portion(130) of FIG. 1D in partial longitudinal cross section, complete withpores (138) traversing through the thickness of portion (130). Suchpores (138) can be parallel to each other as shown in FIG. 1E, or theymay be perpendicularly, radially, or even randomly oriented in thedevice body.

A trio of markers is also shown in FIG. 1D evenly aligned along the bodylongitudinal axis (140). Barb marker (156), spherical marker (150), andring-shaped marker (154) demonstrate the use of different multiplemarkers in a single body (110). As previously described, such a designhelps a physician to determine the spatial orientation of the inventivedevice when it is deployed in a biopsy cavity. Although the barb marker(156) is illustrated in a ‘V’ configuration, it is an important aspectof the barb marker (156) to have a shape that is clearly not spherical.This allows the barb marker (156) to be easily distinguished fromcalcifications that may be observed during any non-invasive imagingtechniques.

FIG. 1F depicts a further embodiment of the present invention in whichbody (112) is enveloped in a outer shell (142) consisting of a layer ofbioabsorbable material such those mentioned above. This configurationallows the perimeter of the biopsy cavity to be marked to avoid exposingthe cavity, in the case of a “dirty” margin where re-excision may benecessary, to remaining cancerous cells as the tissue begins to re-growinto the cavity. Such a shell (142) can be radiopaque and/or echogenicin situ, or it may be augmented with an additional coating of anechogenic and/or radiopaque material. The shell (142) can also be madeto be palpable so that the physician or patient can be further aided indetermining the location and integrity of the implanted inventivedevice.

Shell (142) may be designed to have a varying bioabsorption ratedepending upon the thickness and type of material making up the shell(142). In general, the shell can be designed to degrade over a periodranging from as long as a year or more to as little as several months,weeks, or even days. It is preferred that such a bioabsorbable shell bedesigned to degrade between two and six months; especially preferred isthree months. In the design of FIG. 1F, interior (144) of body (112) maybe a cross-linked, collagenous material that is readily absorbed by thehuman or mammalian body once the shell (142) degrades. Interior (144)may be filled with a solid or gelatinous material that can be optionallymade radiopaque by any number of techniques herein described.

As will be described in additional detail with respect to FIGS. 2A-2F,marker (150) in the device shown in FIG. 1F may be permanentlyradiopaque or echogenic, or it also may be bioabsorbable and optionallycoated with a radiopaque and/or echogenic coating that similarlydegrades over a predetermined period of time. It is more important froma clinical standpoint that the marker remain detectable eitherpermanently or, if the patient is uncomfortable with such a scenario,for at least a period of about one to five years so that the physicianmay follow up with the patient to ensure the health of the tissue in thevicinity of the biopsy cavity. Especially preferable is a marker whoseradiopacity or echogenicity lasts from between about one and threeyears.

Each of the bodies depicted in FIGS. 1A-1E may be made from a widevariety of solid, liquid, aerosol-spray, spongy, or expanding gelatinousbioabsorbable materials such as collagen, cross-linked collagen,regenerated cellulose, synthetic polymers, synthetic proteins, andcombinations thereof. Also contemplated is a body made from afibrin-collagen matrix, which further prevent unnecessary bleeding, andminimizes the possibility of hematoma formation.

Examples of synthetic bioabsorbable polymers that may be used for thebody of the device are polyglycolide, or polyglycolic acid (PGA),polylactide, or polylactic acid (PLA), poly ε-caprolactone,polydioxanone, polylactide-co-glycolide, e.g., block or randomcopolymers of PGA and PLA, and other commercial bioabsorbable medicalpolymers. Preferred is spongy collagen or cellulose. As mentioned above,materials such as hemostatic and pain-killing substances may beincorporated into the body and marker of the cavity marking device. Theuse of hemostasis-promoting agents provides an obvious benefit as thedevice not only marks the site of the biopsy cavity but it aids inhealing the cavity as well. Furthermore, such agents help to avoidhematomas. These hemostatic agents may include AVITENE MicrofibrillarCollagen Hemostat, ACTIFOAM collagen sponge, sold by C. R. Bard Inc.,GELFOAM, manufactured by Upjohn Company, SURGICEL Fibrillar from EthiconEndosurgeries, Inc., and TISSEEL VH, a surgical fibrin sealant sold byBaxter Healthcare Corp. The device may also be made to emit therapeuticradiation to preferentially treat any suspect tissue remaining in oraround the margin of the biopsy cavity. It is envisioned that the markerwould be the best vehicle for dispensing such local radiation treatmentor similar therapy. Also, the body itself may be adapted to haveradiopaque, echogenic, or other characteristics that allow the body tobe located by non-invasive technique without the use of a marker. Suchcharacteristics permit the possibility of locating and substantiallyidentifying the cavity periphery after deployment but prior toabsorption of the device. Furthermore, an echogenic coating may beplaced over the radiopaque marker to increase the accuracy of locatingthe marker during ultrasound imaging.

FIGS. 2A-2F illustrate various forms of the marker (110). The marker(110) may be in the form of a sphere (150) (FIG. 2A), a hollow sphere(152) (FIG. 2B), a ring or band (154) (FIG. 2C), a barb (156) (FIG. 2D),or a flexible suture or flexible wire (158) (FIG. 2E). Also, the markermay have a distinguishing mark (170) (FIG. 2F). As mentioned above, thebarb (156) is illustrated in FIG. 2D as having a “V” shape. The barb(156) is intended to distinguish the marker from calcifications whenviewed under non-invasive imaging techniques. As such, the barb (156) isnot limited to the “V” shape, rather it has a shape that is easilydistinguishable from a spherical or oval calcification.

The hollow sphere (152) marker design of FIG. 2B is more susceptible todetection by ultrasound than the solid sphere (150) of FIG. 2A. Suchsphere markers (150, 152) can be a silicon bead, for instance. In thecase of a ring or band marker (154) seen in FIG. 2C, the body of thecavity marking device may be woven or placed through the band/ring(154). The marker may also be a wire or suture (158) as shown in FIG. 2Eand as discussed in greater detail below. In such a case, the marker(158) may be affixed to the exterior perimeter of the body by anadhesive or woven through the body. Another improvement may arise fromthe marker wire or suture (158) being configured in a particular patternwithin the body of the device, e.g., wrapping around the body in ahelical manner. Further, the suture or wire marker can be deployed as aloosely wound ball or mass of suture that when deployed into a tissuecavity, fills the cavity. The suture or wire can also looped through theband/ring (154); in this configuration (not shown), the suture or wirecan also act as the body of the inventive device. The suture or wire(158) is flexible to facilitate the expansion of the body while in thecavity. In the case of the marker (150) shown in FIG. 2F, distinguishingor identifying mark (170) can be in the form of simple marks as shown,or it may be one or more numbers, letters, symbols, or combinationsthereof. These marks (170) are preferably located in more than onelocation on the marker (150) so that the marker may be readily andsimply identified from multiple orientations under a variety of viewingconditions. Such a mark (170) can be used to identify the patient andher condition, provide information about the marker and body of thetissue cavity marking device, provide information about thecircumstances and date of the implantation, who performed the procedure,where the procedure was performed, etc. In the case of multiple biopsysites, this distinguishing mark (170) permits one to differentiate andidentify each different site. The mark (170) may be applied via anynumber of techniques such as physical inscription, physical or plasmadeposition, casting, adhesives, etc. The mark (170) may also be anelectronic chip providing any necessary information in electronic formthat can be remotely detected by appropriate means.

An important aspect of the invention is that the marker may beradiopaque, echogenic, mammographic, etc. so that it can be located bynon-invasive techniques. Such a feature can be an inherent property ofthe material used for the marker. Alternatively, a coating or the likecan be added to the marker to render the marker detectable or to enhanceits detectability. For radiopacity, the marker may be made of anon-bioabsorbable radiopaque material such as platinum,platinum-iridium, platinum-nickel, platinum-tungsten, gold, silver,rhodium, tungsten, tantalum, titanium, nickel, nickel-titanium, theiralloys, and stainless steel or any combination of these metals. Bymammographic we mean that the component described is visible underradiography or any other traditional or advanced mammography techniquein which breast tissue is imaged.

As previously discussed, the marker can alternatively be made of orcoated with a bioabsorbable material. In this case, the marker can, forinstance, be made from an additive-loaded polymer. The additive is aradiopaque, echogenic, or other type of substance that allows for thenon-invasive detection of the marker. In the case of radiopaqueadditives, elements such as barium- and bismuth-containing compounds, aswell as particulate radio-opaque fillers, e.g., powdered tantalum ortungsten, barium carbonate, bismuth oxide, barium sulfate, etc. arepreferred. To aid in detection by ultrasound or similar imagingtechniques, any component of the device may be combined with anechogenic coating. One such coating is ECHO-COAT from STS Biopolymers.Such coatings contain echogenic features which provide the coated itemwith an acoustically reflective interface and a large acousticalimpedance differential. As stated above, an echogenic coating may beplaced over a radiopaque marker to increase the accuracy of locating themarker during ultrasound imaging.

Note that the radiopacity and echogenicity described herein for themarker and the body are not mutually exclusive. It is within the scopeof the present invention for the marker or the body to be radiopaque butnot necessarily echogenic, and for the marker or the body to beechogenic but not necessarily radiopaque. It is also within the scope ofthe invention that the marker and the body are both capable of beingsimultaneously radiopaque and echogenic. For example, if a platinum ringmarker were coated with an echogenic coating, such a marker would bereadily visible under x-ray and ultrasonic energy. A similarconfiguration can be envisioned for the body or for a body coating.

The marker is preferably large enough to be readily visible to thephysician under x-ray or ultrasonic viewing, for example, yet be smallenough to be able to be percutaneously deployed into the biopsy cavityand to not cause any difficulties with the patient. More specifically,the marker will not be large enough to be palpable or felt by thepatient.

Another useful version of the invention is shown in FIG. 3A. In thisdevice, there are several cylindrical body members (302); however, thereis no limit to the number of body members that can make up the device.The body members (302) can individually or together take on a variety ofsizes and shapes as discussed above depending on the characteristics ofthe biopsy cavity to be filled. The body members (302) may uniformly orin combination be made of one or more materials suitable for use in abiopsy cavity as previously described.

Here one or more markers may traverse two or more body member segmentsthrough the interior of the body members (302) as shown in FIG. 3A.Here, markers (318) are located substantially parallel to thelongitudinal axis (320) of each right cylindrical body member (302) intheir interior, connecting each body member (302) while marking theirgeometric center as between the markers. Such a marker (318) may be usedin conjunction with the other markers as described above and may also beaccompanied by one or more additional markers arranged randomly or in apredetermined pattern to variously mark particular sections of thedevice. Alternately, such a marker may, singly or in combination withother markers, be affixed on or near the surface of the sponge so as tomark the perimeter of the body member (302).

Of course, when used in conjunction with other connecting markers,marker (318) need not necessarily connect each body member; it may beused solely to indicate the orientation or location of each individualsponge or the entire device, depending on the material, geometry, size,orientation, etc. of marker (318). When not used in this connectingfunction, therefore, marker (318) need not traverse two body members(302) as shown in FIG. 3A.

A variety of patterns can be envisioned in which all or part of theperimeter of the sponge body is marked. For example, a marker (322) canwrap around the body (302) in a helical pattern (FIG. 3B), or it can beused in conjunction with other markers (324) in a pattern parallel tothe longitudinal axis (320) of the body (FIG. 3C). Another usefulperimeter marking pattern is shown in FIG. 3D, where marker segments(326) are affixed at or near the surface of the circular bases of thecylindrical body (302) in a cross pattern, indicating the ends of thesponge and their center. As seen form the figures, the markers(s) may,but do not necessarily, have some texture. Any marker pattern, internalor external to the body, is within the scope of the present invention.For the applications depicted in FIGS. 3A-3D, it is preferred that themarker be a radiopaque or echogenic wire or suture.

Another possible configuration is obtained by combining the suture orwire markers (158) in a body with any other type marker (150, 152, 154,or 156) or vice versa. For example, in FIG. 3B, a spherical marker (150)may be placed in the center of the cylindrical body (302.) Therefore,the cylindrical body (302) would contain the suture or wire marker (322)wrapped helically adjacent to the outer perimeter, and a marker (150)would be placed in the center of the cylindrical body (302). Such acombination may be obtained with any of the body and markerconfigurations as defined above.

Also, turning back to the marking device (100) in FIG. 1A or the markingdevice (100) of FIG. 1B, the markers (150 or 154) may be substitutedwith one or more suture or wire markers (158) preferably, but notexclusively, extending through the center and pointing radially awayfrom the center. This configuration allows marking of the cavityperimeter and establishing of the directionality of the cavity itself.

Any of the previously-described additional features of the inventivedevice, such as presence of pain-killing or hemostatic drugs, thecapacity for the marker to emit therapeutic radiation for the treatmentof various cancers, the various materials that may make up the markerand body, as well as their size, shape, orientation, geometry, etc. maybe incorporated into the device described above in conjunction withFIGS. 3A-3D.

Turning now to FIGS. 4A-4C, a method of delivering the inventive deviceof FIG. 1A is shown. FIG. 4A details the marking device (402) just priorto delivery into a tissue cavity (404) of human or other mammaliantissue, preferably breast tissue (406). As can be seen, the stepillustrated in FIG. 4A shows a suitable tubular percutaneous accessdevice (400), such as a catheter or delivery tube, with a distal end(408) disposed in the interior of cavity (404). As previously described,the marking device (402) may be delivered percutaneously through thesame access device (400) used to perform the biopsy in which tissue wasremoved from cavity (404). Although this is not necessary, it is lesstraumatic to the patient and allows more precise placement of themarking device (402) before fluid begins to fill the cavity (400).

In FIG. 4B, marking device (402) is shown being pushed out of the distalend (408) of access device (400) by a pusher (412) and resilientlyexpanding to substantially fill the tissue cavity (404).

Finally, in FIG. 4C, access device (400) is withdrawn from the breasttissue, leaving marking device (402) deployed to substantially fill theentire cavity (404) with radiopaque or echogenic marker (410) suspendedin the geometric center of the marking device (402) and the cavity(404). As mentioned above, the marking device (402) may be sized to belarger than the cavity (404) thus providing a significant resistanceagainst the walls of the cavity (404).

FIGS. 4D-4F show a method of delivering the marking device (402) into atissue cavity (404) by a plunger (414) that is capable of both advancingthe marking device (402) and delivering a bio-compatible fluid (416).The “bio-compatible fluid” is a liquid, solution, or suspension that maycontain inorganic or organic material. The fluid (416) is preferably asaline solution, but may be water or contain adjuvants such asmedications to prevent infection, reduce pain, or the like. Obviously,the fluid (416) is intended to be a type that does no harm to the body.

FIG. 4D details the marking device (402) prior to delivery into thetissue cavity (404). In FIG. 4E, a plunger (414) pushes the markingdevice (402) out of the access device (400). Upon exiting the ac cessdevice (400) the marking device (402) begins resiliently expanding tosubstantially fill the cavity (404).

FIG. 4F shows the plunger (414) delivering the bio-compatible fluid(416) into the cavity (404). The fluid (416) aids the marking device(402) in expanding to substantially fill the cavity (404). In thisexample, the bio-compatible fluid (416) is delivered subsequent to theplacement of the marking device (402) in the cavity (404). The markingdevice (402) may also be soaked with fluid (416) prior to placement inthe cavity (404).

FIGS. 4G-4I show another method of delivering the marking device (402)into the tissue cavity (404) by using the bio-compatible fluid (416) asthe force to deliver the marking device (402) into the tissue cavity(404).

FIG. 4G details the marking device (402) prior to delivery into thetissue cavity (404). FIG. 4H illustrates flow of the bio-compatiblefluid (416) in the access device (400), the fluid (416) flow then pushesthe marking device (402) out of the access device (400).

FIG. 4I shows the delivery device (400) continuing to deliver thebio-compatible fluid (416) into the cavity (404). The fluid (416) aidsthe marking device (402) in expanding to substantially fill the cavity(404). In this example, the bio-compatible fluid (416) is deliveredafter the placement of the marking device (402) in the cavity (404)although the invention is not limited to the continued delivery of thefluid (416).

FIG. 4J-4K shows the method of delivering the body (418) of the cavitymarking device directly into the cavity (404) prior to the placement ofthe marker (410) in the device (402).

FIG. 4J shows the deposit of the body material (418) into the cavity(404). In this case the body material (418) may be a gel type materialas described above. FIG. 4K details the filling of the cavity (404) withthe body material (418). At this point, the delivery device (not shownin FIG. 4K) may be withdrawn. FIG. 4L details the placement of themarker (410) into the body material (418).

FIGS. 5A-5E show yet another version of the invention in which a marker,preferably consisting of a radiopaque or echogenic wire, is deployedalone into a tissue cavity without the use of any body. In this device,the marker can be made of a shape memory material, such as anickel-titanium alloy, which when deployed into the biopsy cavity,assumes a predetermined configuration to substantially fill the cavity,mark the cavity location and margin, and indicate the orientation of themarker inside the cavity.

In FIG. 5A, marker (500) is a three-dimensional sphere consisting of tworings (502), (504) pivotally connected at ends (506), (508) so to assumea spherical shape. Such a marker can be made of a shape memory metal sothat when it is placed in a deployment tube (510) shown in FIG. 5B,marker (500) assumes a collapsed profile suitable for deployment throughtube (510) by pusher (512). Upon exiting into the tissue cavity (notshown), marker (500) assumes the spherical shape of FIG. 5A to fill thecavity. The marker (500) may also be shaped into any similar shape suchas an ellipsoidal shape.

Turning now to FIG. 5C, a marker (520) in the form of a wire cylinder isshown. Again, this device is structurally configured to assume thedepicted cylindrical configuration when deployed in the tissue cavity,but may be (as described above) “collapsed” into a deployment tube forpercutaneous delivery. This device is especially suitable for markingthe distal and proximal ends of the tissue cavity due to itsasymmetrical shape.

FIG. 5D shows a shape memory marker (530) in the form of a helical coildeployed into tissue cavity (532). Again, as seen in FIG. 5E, such amarker (530) may be deployed through delivery tube (510) by pusher (512)in a substantially elongated, straightened form, only to substantiallyassume the shape of the cavity (532) as shown in FIG. 5D. Any suitabledelivery device or pusher (512) capable of deploying marker (530) intocavity (532) is within the scope of this invention.

Each of the markers shown in FIGS. 5A-5E is preferably a shape memorymaterial coated or supplemented with a radiopacity-enhancing material,such as gold, platinum, or any other radiopaque material hereindiscussed. The markers may singly, or in combination with beingradiopaque, be echogenic or be made echogenic by any of the materials ormethods herein described.

From the foregoing, it is understood that the invention provides animproved subcutaneous cavity marking device and method. While the abovedescriptions have described the invention for use in the marking ofbiopsy cavities, the invention is not limited to such. One suchapplication is evident as the invention may further be used as alumpectomy site marker. In this use, the cavity marking device yield animproved benefit by marking the perimeter of the lumpectomy cavity.

The invention herein has been described by examples and a particularlydesired way of practicing the invention has been described. However, theinvention as claimed herein is not limited to that specific descriptionin any manner. Equivalence to the description as hereinafter claimed isconsidered to be within the scope of protection of this patent.

We claim as our invention:
 1. A subcutaneous cavity marking devicecomprising: (a) at least one filler body comprising a resilientbioabsorbable material, and (b) at least one detectable marker attachedto said filler body and adapted to mark a center of said filler body,wherein said marker is mammographic.
 2. The device of claim 1 whereinthe at least one marker comprises a non-bioabsorbable material.
 3. Thedevice of claim 2 wherein the marker comprises a material selected fromthe group consisting of platinum, iridium, nickel, tungsten, tantalum,gold, silver, rhodium, titanium, alloys thereof, and stainless steel. 4.The device of claim 1 wherein the at least one marker comprises a secondbioabsorbable material.
 5. The device of claim 4 wherein the secondbioabsorbable material comprises a polymer having a radiopaque additive.6. The device of claim 5 wherein the radiopaque additive is selectedfrom the group consisting of barium-containing compounds,bismuth-containing compounds, powdered tantalum, powdered tungsten,barium carbonate, bismuth oxide, and barium sulfate.
 7. The device ofclaim 1 wherein the at least one marker is radiopaque.
 8. The device ofclaim 1 wherein the at least one body is radiopaque.
 9. The device ofclaim 1 wherein the at least one marker is echogenic.
 10. The device ofclaim 1 wherein the at least one body is echogenic.
 11. The device ofclaim 1 wherein the at least one body is mammographic.
 12. The device ofclaim 1 wherein the at least one body is palpable.
 13. The device ofclaim 12 wherein after insertion of said device into a patient saidmarker is not locatable by tactile detection.
 14. The device of claim 1wherein the marker is located within an interior of the at least onebody.
 15. The device of claim 1 wherein the marker is substantiallylocated within a geometric center of the at least one body.
 16. Thedevice of claim 1 additionally comprising a pain killing substance. 17.The device of claim 1 additionally comprising a hemostatic substance.18. The device of claim 1 wherein the bioabsorbable material is selectedfrom the group consisting of collagen, regenerated cellulose, syntheticpolymers and synthetic proteins.
 19. The device of claim 1 wherein themarker has a form of a sphere.
 20. The device of claim 19 wherein thesphere is hollow.
 21. The device of claim 1 wherein the marker has aform of a band.
 22. The device of claim 1 wherein the marker comprises asuture.
 23. The device of claim 1 wherein the marker comprises a wire.24. The device of claim 1 wherein the marker has a distinguishing mark.25. The device of claim 1 wherein the marker is fixedly attached to theat least one body.
 26. The device of claim 25 wherein the marker iswoven to the at least one body.
 27. The device of claim 1 wherein themarker is radioactive.
 28. The device of claim 1 wherein the at leastone body is radioactive.
 29. The device of claim 1 wherein the at leastone body is substantially spherical.
 30. The device of claim 1 whereinthe at least one body is substantially cylindrical.
 31. The device ofclaim 1 wherein the at least one body is has a substantially irregularshape.
 32. The device of claim 1 wherein the at least one body comprisesa plurality of pores.
 33. The device of claim 32 wherein the pores areconfigured to promote tissue growth in a preferred orientation.
 34. Thedevice of claim 1 wherein the at least one filler body additionallycomprises a bio-compatible liquid.
 35. The device of claim 1 whereinsaid filler body further comprises a palpable shell.
 36. The device ofclaim 35 wherein said shell is bioabsorbable and degrades when implantedwithin a patient's body, after said shell degrades said shell is nolonger palpable.
 37. The device of claim 36 wherein said shell isconfigured to degrade over a period of time.
 38. The device of claim 37wherein said period of time is less than 1 year.
 39. The device of claim37 wherein said period of time is between 2 and 6 months.
 40. The deviceof claim 37 wherein said period of time is about 3 months.
 41. Thedevice of claim 1 wherein after a period of time said body is notpalpable.
 42. The device of claim 41 wherein said period of time isapproximately 3 months.
 43. A subcutaneous cavity marking devicecomprising: (a) at least one filler body comprising a resilientbioabsorbable material, wherein the at least one body is mammographic,and (b) at least one detectable marker attached to said filler body andadapted to mark a center of said filler body.
 44. The device of claim 43wherein the at least one marker comprises a non-bioabsorbable material.45. The device of claim 44 wherein the marker comprises a materialselected from the group consisting of platinum, iridium, nickel,tungsten, tantalum, gold, silver, rhodium, titanium, alloys thereof, andstainless steel.
 46. The device of claim 43 wherein the at least onemarker comprises a second bioabsorbable material.
 47. The device ofclaim 46 wherein the second bioabsorbable material comprises a polymerhaving a radiopaque additive.
 48. The device of claim 47 wherein theradiopaque additive is selected from the group consisting ofbarium-containing compounds, bismuth-containing compounds, powderedtantalum, powdered tungsten, barium carbonate, bismuth oxide, and bariumsulfate.
 49. The device of claim 43 wherein the at least one marker isradiopaque.
 50. The device of claim 43 wherein the at least one body isradiopaque.
 51. The device of claim 43 wherein the at least one markeris echogenic.
 52. The device of claim 43 wherein the at least one bodyis echogenic.
 53. The device of claim 43 wherein the at least one bodyis palpable.
 54. The device of claim 53 wherein after insertion of saiddevice into apatient said marker is not locatable by tactile detection.55. The device of claim 43 wherein the marker is located within aninterior of the at least one body.
 56. The device of claim 43 whereinthe marker is substantially located within a geometric center of the atleast one body.
 57. The device of claim 43 additionally comprising apain killing substance.
 58. The device of claim 43 additionallycomprising a hemostatic substance.
 59. The device of claim 43 whereinthe bioabsorbable material is selected from the group consisting ofcollagen, regenerated cellulose, synthetic polymers and syntheticproteins.
 60. The device of claim 43 wherein the marker has a form of asphere.
 61. The device of claim 60 wherein the sphere is hollow.
 62. Thedevice of claim 43 wherein the marker has a form of a band.
 63. Thedevice of claim 43 wherein the marker comprises a suture.
 64. The deviceof claim 43 wherein the marker comprises a wire.
 65. The device of claim43 wherein the marker has a distinguishing mark.
 66. The device of claim43 wherein the marker is fixedly attached to the at least one body. 67.The device of claim 66 wherein the marker is woven to the at least onebody.
 68. The device of claim 43 wherein the marker is radioactive. 69.The device of claim 43 wherein the at least one body is radioactive. 70.The device of claim 43 wherein the at least one body is substantiallyspherical.
 71. The device of claim 43 wherein the at least one body issubstantially cylindrical.
 72. The device of claim 43 wherein the atleast one body is has a substantially irregular shape.
 73. The device ofclaim 43 wherein the at least one body comprises a plurality of pores.74. The device of claim 73 wherein the pores are configured to promotetissue growth in a preferred orientation.
 75. The device of claim 43wherein the at least one filler body additionally comprises abio-compatible liquid.
 76. The device of claim 43 wherein said fillerbody further comprises a palpable shell.
 77. The device of claim 76wherein said shell is bioabsorbable and degrades when implanted within apatient's body, after said shell degrades said shell is no longerpalpable.
 78. The device of claim 77 wherein said shell is configured todegrade over a period of time.
 79. The device of claim 78 wherein saidperiod of time is less than 1 year.
 80. The device of claim 78 whereinsaid period of time is between 2 and 6 months.
 81. The device of claim78 wherein said period of time is about 3 months.
 82. The device ofclaim 43 wherein after a period of time said body is not palpable. 83.The device of claim 82 wherein said period of time is approximately 3months.
 84. A method of marking a tissue cavity having a margin in amammalian body, comprising: (a) subcutaneously accessing the cavity viaa delivery device, (b) introducing a biocompatible liquid in aremotely-detectable marker having a predetermined shape; and thereafter(c) deploying the marker through the delivery device into the cavity,wherein upon delivery into the cavity the marker assumes a predeterminedthree-dimensional configuration so to (1) substantially fill the cavity,(2) mark the cavity margin, and (3) indicate the orientation of themarker inside the cavity.
 85. The method of claim 84 wherein the markeris bioabsorbable.
 86. The method of claim 84 wherein the marker isradiopaque.
 87. The method of claim 84 wherein the marker is echogenic.88. The method of claim 84 wherein the marker comprises a wire.
 89. Themethod of claim 85 wherein the wire comprises a shape memory material.90. The method of claim 84 wherein the marker comprises a materialselected from the group consisting of platinum, iridium, nickel,tungsten, tantalum, gold, silver, rhodium, titanium, alloys thereof, andstainless steel.
 91. The method of claim 84 wherein the marker iscapable of emitting radioactive energy.
 92. The method of claim 84wherein the marker is a helical coil.
 93. The method of claim 84 whereinthe marker defines a volume having a substantially spherical shape whenthe marker is deployed inside the cavity.
 94. The method of claim 84wherein the marker defines a volume comprising a substantiallycylindrical shape when the marker is deployed inside the cavity.
 95. Themethod of claim 84 wherein the marker defines a volume comprising arandom shape when the marker is deployed inside the cavity.
 96. Themethod of claim 84 wherein the delivery device uses a hydraulic force todeploy the marker.
 97. The method of claim 84 wherein the deliverydevice comprises a biopsy device.
 98. A method of marking a tissuecavity having a margin in a mammalian body, comprising: (a)subcutaneously accessing the cavity via a delivery device, (b) deployinga remotely detectable marker having a predetermined shape through thedelivery device into the cavity, and thereafter (c) introducing abiocompatible liquid in the marker, wherein upon delivery into thecavity the marker assumes a predetermined three-dimensionalconfiguration so to (1) substantially fill the cavity, (2) mark thecavity margin, and (3) indicate the orientation of the marker inside thecavity.
 99. The method of claim 98 wherein the bio-compatible liquid isintroduced to the marker via the delivery device.
 100. The method ofclaim 98 wherein the marker is bioabsorbable.
 101. The method of claim98 wherein the marker is radiopaque.
 102. The method of claim 98 whereinthe marker is echogenic.
 103. The method of claim 98 wherein the markercomprises a wire.
 104. The method of claim 103 wherein the wirecomprises a shape memory material.
 105. The method of claim 104 whereinthe marker comprises a material selected from the group consisting ofplatinum, iridium, nickel, tungsten, tantalum, gold, silver, rhodium,titanium, alloys thereof, and stainless steel.
 106. The method of claim104 wherein the marker is capable of emitting radioactive energy. 107.The method of claim 104 wherein the marker is a helical coil.
 108. Themethod of claim 104 wherein the marker defines a volume having asubstantially spherical shape when the marker is deployed inside thecavity.
 109. The method of claim 104 wherein the marker defines a volumecomprising a substantially cylindrical shape when the marker is deployedinside the cavity.
 110. The method of claim 104 wherein the markerdefines a volume comprising a random shape when the marker is deployedinside the cavity.
 111. The method of claim 104 wherein the deliverydevice comprises a biopsy device.